The exemplary embodiment relates to the field of image processing. It finds particular application in connection with the provision of feedback on the automated enhancement of digital images, and is described with particular reference thereto. However, it is to be appreciated that it may find more general application in image classification, image content analysis, image archiving, image database management and searching, and so forth.
Photographers are now using digital image capture devices, such as cameras, cell phones, and optical scanners, to capture images in digital format. The captured images are often sent to photofinishing services or content-sharing communities. Regardless of the final medium in which the images will be managed, shared and visualized, the quality expectations of users are growing. These services often make use of automated or semi-automated enhancement methods to correct detected degradations in an image. For example, features such as automatic color balance or red-eye correction are now standard components in many image editing applications. Acquisition conditions, user expertise, compression algorithms and sensor quality can seriously degrade the final image quality. Image enhancement tools attempt to compensate for this degradation by altering image features for subsequent analysis, distribution or display. Examples of these image features include contrast and edge enhancement, noise filtering for a wide variety of noise sources, sharpening, exposure correction, color balance adjustment, automatic cropping, and correction of shaky images. Traditional photofinishing services available online enable clients to enhance images manually or automatically through proprietary algorithms before printing however, no feedback is given to clients on the quality of the original images and on the effect of the applied enhancements in the final prints.
When the enhancements are performed automatically, without user input, the amateur photographer may not notice the enhancements without a close inspection of the finished product, and thus is often unaware that the photofinishing service has considerably improved the visual appearance of the image in the process. Moreover, the photographer does not appreciate that changes in shooting techniques could avoid similar image degradations in the future. Perceiving the quality of a digital image is in general a difficult exercise for non-expert users. In particular, it is not easy to spot specific degradations (e.g., low contrast vs. low saturation, incorrect white balance, and the like) or to understand how these degradations could have been avoided at the time the photo was taken.